obbvtk定点坐标_VTK三维坐标点拾取

三维坐标拾取&＃xff0c;可以借助vtkPointPicker或者vtkCellPicker&＃xff0c;其官方例程序参见annotatePick.py或QtVTKRenderWindows.cxx。

QtVTKRenderWindows.cxx例子中说明&＃xff0c;如果将vtkCellPicker与vtkImagePlaneWidget结合使用时&＃xff0c;只需要使用vtkImagePlaneWidget的SetPicker()将它们两者绑定即可实现坐标点的拾取和显示&＃xff1b;然而&＃xff0c;如果想在三维重建时&＃xff0c;实现目标的三维坐标拾取&＃xff0c;可不那么简单。下面是VTK6.2.0的使用文档中对含有SetPicker()函数的类的总结&＃xff1a;

SetPicker() : vtkRenderWindowInteractor , vtkBalloonWidget , vtkImagePlaneWidget

由上面的总结可见&＃xff0c;只有3个类是含有SetPicker()函数的&＃xff0c;也就是说只有3个类可以与vtkCellPicker绑定。在三维重建效果显示时&＃xff0c;通常使用的是第1个&＃xff1a;vtkRenderWindowInteractor。

将vtkCellPicker与vtkRenderWindowInteractor通过SetPicker()绑定之后&＃xff0c;并非就万事大吉。这时候还不能触发三维坐标点的采集。此外&＃xff0c;就算继续设定vtkCellPicker的事件处理函数&＃xff0c;也还不行。

那么&＃xff0c;要怎样才能触发vtkCellPicker的采集呢&＃xff1f;答案是必须调用其Pick()函数&＃xff0c;而且是调用一次&＃xff0c;就触发一次&＃xff01;下面将用一个实例说明。

1 vtkCellPicker的创建并且与Interactor绑定

// Cell Picker

m_pvtkCellPicker &＃61;

vtkSmartPointer::New();

m_pvtkCellPicker->SetTolerance( 0.005 );

vtkSmartPointer callback_picker &＃61; vtkSmartPointer ::New();

callback_picker->SetCallback( handle_cell_picker );

callback_picker->SetClientData( this );

m_pvtkCellPicker->AddObserver( vtkCommand::EndPickEvent, callback_picker );

this->ui->qvtkWidget3D->GetInteractor()->SetPicker( m_pvtkCellPicker );

2 vtkCellPicker回调函数

static void handle_cell_picker(vtkObject *caller, unsigned long eid, void *clientdata, void *calldata)

{

QString hints;

double selPt[3];

double normal[3];

//float pixelValue &＃61; 0;

RSAMeasurement3D *parent&＃61; (RSAMeasurement3D *)clientdata;

if ( !parent )

return;

if ( !parent->m_bHasRendered3D ) {

parent->m_pvtkTextActor->VisibilityOff();

return;

}

if ( Qt::Unchecked &＃61;&＃61; parent->ui->enablePickerCheckBox->checkState() ) {

// parent->m_pvtkTextActor->VisibilityOff();

return;

}

if ( parent->m_pvtkCellPicker->GetCellId() <0)

return;

parent->m_pvtkCellPicker->GetPickPosition( selPt );

parent->m_pvtkTextActor->VisibilityOn();

parent->m_pvtkConeActor->SetPosition( selPt );

}

3 触发坐标点采集

我们的设想是&＃xff0c;点击以下鼠标&＃xff0c;采集一次坐标。首先要设置Interactor的单击处理回调函数&＃xff1a;

vtkSmartPointer callback_interactor &＃61;

vtkSmartPointer ::New();

callback_interactor->SetCallback( handle_interactor_event );

callback_interactor->SetClientData( this );

this->ui->qvtkWidget3D->GetInteractor()->AddObserver(

vtkCommand::LeftButtonPressEvent, callback_interactor );    在回调函数里面&＃xff0c;触发坐标采集

static void handle_interactor_event(vtkObject *caller, unsigned long eid, void *clientdata, void *calldata)

{

//qDebug() <<"left button release";

RSAMeasurement3D *parent&＃61; (RSAMeasurement3D *)clientdata;

if ( !parent )

return;

int *pick &＃61; parent->ui->qvtkWidget3D->GetInteractor()->GetEventPosition();

parent->m_pvtkCellPicker->Pick(

(double)pick[0],

(double)pick[1],

0.0,

parent->m_pvtkRenderer3D );

}

参考资料

[1]VTK拾取三维空间细胞(vtkcell)坐标参数

[2]vtk捡选实例

[3]vtk坐标系统

[4]VTK拾取相关的类(转)

[5]用vtk在屏幕中选一个点,并加上标记

[6][vtkusers] vtkCellPicker failing to pick vtkPolyLine (using Python and wx)